I could never get this to work in any version of MAME. Today I finally found a working rom, although it only works in vanilla MAME, so no autofire for me this time. Had 4 goes and looking at your scores I'm clearly missing something about scoring here.

The higher up the screen you are when you collect a money symbol, the greater it's value. You can get 10,000 if you are at the very top of the screen, you need to memorise where to find the money and practice the bonus levels.

Also when you shoot the plane that pops out of the boss at the end of the 1st and 4th levels it determines your route, depending on whether you shoot the left or right wing. You get more points going left first but I'm still working out a preferred route and character for the rest of it. The neo geo doesn't allow autofire either so the MAME version you have is probably working correctly.